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Proceedings Paper

Amorphous silicon thin film for all-optical micromodulator
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Paper Abstract

Photoinduced absorption by VIS radiation in a-Si:H has been studied in-guide, in order to realise a novel all-optical waveguide micromodulator for application at 1.3 and 1.55 μm fiber communication wavelengths. In a-Si:H the photoinduced effects and the NIR absorption both involve dangling bonds states. The density of these states, deep in the gap, can be varied with doping. Therefore three waveguide prototypes have been fabricated by Plasma Enhanced Chemical Vapour Deposition on a silicon wafer. Their structure consist of a a-Si:H/SiO2 stack where the a-Si:H cores have different doping. The upper cladding is air. Optical measures on the core materials and signal transmission analysis in-guide at bit rates up to 200 kBit/s have been carried out. The excitation source of the VIS pump system for in-guide analysis consisted of simple, low cost AlInGaP LED’s controlled by a pulse generator. The pump and probe measures have been performed with different pump wavelengths and by varying the illumination intensity. LED’s with wavelengths of 644, 612, 590 and 571 nm have been alternatively used. For each pump wavelength, the light intensity was varied between 0,15 and 0,85 mW/mm2. The results confirms that the optical modulation of the NIR signal enhances at high doping levels and for longer wavelengths. The modulation speed is probably limited by recombination phenomena.

Paper Details

Date Published: 24 April 2003
PDF: 8 pages
Proc. SPIE 5116, Smart Sensors, Actuators, and MEMS, (24 April 2003); doi: 10.1117/12.499142
Show Author Affiliations
Maria Arcangela M.N. Nigro, Univ. degli Studi di Reggio Calabria (Italy)
Francesca Cantore, Univ. degli Studi di Reggio Calabria (Italy)
Francesco Giuseppe Della Corte, Univ. degli Studi di Reggio Calabria (Italy)
IMM-National Research Council (Italy)
Caterina Summonte, Consiglio Nazionale delle Ricerche (Italy)

Published in SPIE Proceedings Vol. 5116:
Smart Sensors, Actuators, and MEMS
Jung-Chih Chiao; Vijay K. Varadan; Carles Cané, Editor(s)

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